1. Field of the Invention
The present invention relates to an apparatus for adjusting the height of the upper attachment or guide fitting for the shoulder belt of a safety belt system, particularly in motor vehicles, and comprises an arrangement for the preferably automatic adaptation of the height position of the attachment or guide fitting to the seat position of the person to be strapped in to achieve an optimum belt position; in this arrangement, in addition to the fitting, there is provided a device which senses the position of the belt strap with respect to one parameter of its operative connection with the person strapped in, and triggers a reaction to the situation ascertained.
2. Description of the Prior Art
In British Application No. 2,110,921 a device of the general type initially mentioned is described, in which the problem is to determine, after the person located on the corresponding seat of the vehicle is strapped in, a condition value concerning the direction in which the shoulder belt of the safety belt system meets the shoulder, and thus the body of the person strapped in, from its upper attachment or guide fitting. If the result is that the actual condition found does not correspond to the recommended optimum, this is signalled to the person strapped in either by an appropriate signal in such a manner that he or she reacts to it and correspondingly corrects the height position of the upper attachment or guide fitting, or the required height adjustment is carried out in a fully automatic and self-acting manner by suitable means.
However, this device has the associated drawback that the height adjustment device immediately follows all movements of the person strapped in due to the direct coupling of the detection of the actual condition and the signal emission or automatic readjustment of the fitting. Any change of the actual condition of the belt position due to even just slight or unique movements of the strappedin vehicle passengers is detected and converted into corresponding signals or automatic adjusting processes. In consequence, for example, the driver is distracted by the more or less continuous signals, and his concentration on the road traffic is thus impaired, or the fitting is continuously shifted at short intervals by a fully automatic height adjusting device.
An object of the present invention is to provide an apparatus of the general type initially mentioned in which a readjustment of the height position of the upper attachment or guide fitting is effected only on the basis of different body proportions of the respective vehicle passengers, or only with permanent changes of his or her seat position.